With 8 kids, presumably at least 2 were beyond the age where they could be safely managed and helped in a home setting, given their mental condition -- nor would there be many sane people lining up to adopt them. It's one thing dealing with a 6 eyar old in this condition, but a totally different thing to deal with an adult-sized teenager in this condition.
Hope they're able to do more for the older kids than they could in the 18th century.